package com.naxian.util;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class Sha2 {

    /**
         * 利用java原生的类实现SHA256加密
         * @param str 加密后的报文
         * @return
         */
    public static String getSHA256(String str){
        MessageDigest messageDigest;
        String encodestr = "";
        try {
            messageDigest = MessageDigest.getInstance("SHA-256");
            messageDigest.update(str.getBytes("UTF-8"));
            encodestr = byte2Hex(messageDigest.digest());
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
     return encodestr;
    }

    /**
         * 将byte转为16进制
         * @param bytes
         * @return
         */
    private static String byte2Hex(byte[] bytes){
     StringBuffer stringBuffer = new StringBuffer();
     String temp = null;
     for (int i=0;i<bytes.length;i++){
         temp = Integer.toHexString(bytes[i] & 0xFF);
         if (temp.length()==1){
             //1得到一位的进行补0操作
             stringBuffer.append("0");
         }
         stringBuffer.append(temp);
     }
     return stringBuffer.toString();
    }

}
